Is there any ramification for a man who wrote a letter to his wife, giving her the choice of Khulʿ, but the letter was not delivered to her until after his return from a 45-month journey?

If the village elder does not inform the woman that her husband has given her a choice, and she is unaware of this and does not annul the contract, then she remains his wife and the marital contract is still valid, because nothing has occurred to nullify the contract.